The present invention relates to a power apparatus, and particularly relates to a power apparatus, a power transmission/distribution unit, and a tripping method therefor, in which an abnormality of insulation caused by a foreign matter inside the apparatus can be diagnosed.
Recently, the demand of electric power has been increasing more and more, and the environment of social lives using electricity has been popularized, so that the supply of a superior electric power has been a social demand. This supply of a superior electric power means that an electric power with less change in voltage as well as in frequency is supplied without service interruption. Therefore a power apparatus must have less troubles. In a power apparatus, for example, in a circuit breaker, a transformer, a bus bar, etc. insulated with an SF.sub.6 gas, a high voltage portion thereof is housed within an air-tight housing, and it is therefore difficult to visually find an abnormality inside this apparatus at the time of inspection.
Various methods of preventive maintenance for detecting an abnormality of an apparatus have been proposed. For example, as disclosed JP-A-55-37868, there has been proposed a method in which an alarm is generated in one of several stages correspondingly to a level detected by a detector.
Such a method of preventive maintenance puts much weight on how to detect accurately a signal relating to partial discharge, without taking into consideration the dealing way of countermeasure for a power apparatus after detecting an abnormality of the power apparatus as a result of deducing the shape and positional condition of a foreign matter moved in the power apparatus by the effect of an electric field. There has been therefore a problem that a maintainer of the power apparatus is perplexed with the countermeasure.